The sample code below illustrates how to use the deque::front
and deque::back
STL functions in Visual C++.
Required Header:
< deque>
reference front();
const_reference front() const;
reference back();
const_reference back() const;
Note: The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.
Description:
The member function front returns a reference to the first element of the controlled sequence, which must be non-empty. The member function back returns a reference to the last element of the controlled sequence, which must be non-empty.
Sample Code:
//////////////////////////////////////////////////////////////////////
//
// Compile options needed: -GX
//
// deque.cpp :
//
// Functions:
//
// front()
//
// back()
//////////////////////////////////////////////////////////////////////
/* Compile options needed:-GX
*/
#include <iostream>
#include <deque>
using namespace std;
typedef deque<char > CHARDEQUE;
void print_contents (CHARDEQUE deque, char*);
void main()
{
//create a with A, B, C and D
CHARDEQUE a;
a.push_back('A');
a.push_back('B');
a.push_back('C');
a.push_back('D');
//print out the contents
print_contents (a,"a");
cout <<"The first element of a is " <<a.front() <<endl;
cout <<"The last element of a is " <<a.back() <<endl;
//now let us modify the first and last elements
//using reference ,front() and back()
CHARDEQUE::reference reffront=a.front();
CHARDEQUE::reference refback=a.back();
reffront='X';
refback='Y';
//print out the contents
print_contents (a,"a");
}
//function to print the contents of deque
void print_contents (CHARDEQUE deque, char *name)
{
CHARDEQUE::iterator pdeque;
cout <<"The contents of "<< name <<" : ";
for(pdeque = deque.begin();
pdeque != deque.end();
pdeque++)
{
cout << *pdeque <<" " ;
}
cout<<endl;
}
Program Output is:
The contents of a : A B C D
The first element of a is A
The last element of a is D
The contents of a : X B C Y